LieConte.] 



TRACHODINI. 191 



3. T. horridus Mann., Bull. Mosc. 1852, 354. 



Alaska and Vancouver Island. The three rows of large elevations on 

 each elytron easily distinguish this species. 



Trrbe VII. otidocephalini. 



In all the preceding tribes the tarsal claws are simple, usuall}' separate 

 and divergent, rarely connate ; in this, as in several of those wh:ch follow, 

 they ai"e toothed ; the tooth, however, is broad and not very prominent, 

 giving the form termed appendiculate. The species are easily known from 

 those of other tribes by the prothorax being narrowed at base, and some- 

 what pedunculate. Several of them are shining black and glabrous, so 

 that they resemble in appearance ants. 



Mr. C. V. Riley, who has hatched several specimens of Ottdocephalns laevi- 

 collis from the galls of Cynips quercus-dlobulus, informs me that they have 

 a general resemblance to an apterous Cynips, 



The other characters of the tribe and genus are as follows : Beak 

 rather stout, straight, nearly as long as the prothorax, subcylindrical, 

 not emarginate at tip; antennal grooves extending in front of the inser- 

 tion of the antennse, converging behind, directed below the eyes, which are 

 distant from the prothorax, rounded, and finely granulated; mandibles of 

 normal form, mentum and labial palpi small, gular peduncle narrow, 

 long; antennfe inserted about one-third from the tip of the beak, scape long, 

 slender, extending to the back part of the eyes; fuuicle 7-jointed; first joint 

 stouter but only slightly longer than the second; 2-7 gradually a little 

 wider, rounded ; club oval pointed, pubescent, feebly annulated. Pro- 

 thorax without postocular lobes ; prosternum broad, short, not emarginate. 

 Mesosternum very narrow between the coxae, side pieces almost longitudi- 

 nally divided. Metasternum long, side pieces very narrow. Ventral seg- 

 ments nearly equal, sutures straight, well marked, intercoxal process obtuse, 

 moderately wide. Front coxte rounded, prominent; middle cox;« rounded 

 not prominent; hind coxjb oval, not extending to the elytral margin. 

 Legs rather long, thighs somewhat clavate, usually toothed; tibiae truncate 

 at tip, not mucronate; articular surface terminal; tarsi dilated, spongy 

 beneath, third joint broader, bilobed; claws divergent, more or less toothed. 

 Elytra elongate-oval, convex, rounded at tip, entirely concealing the 

 pygidium. ' 



OTIDOCEPHALUS Chevr. 



I have but one species to add to the synopsis given by Dr. Horn, in Proc 

 Am. Phil. Soc. 1873, p. 448.* 



O. dichrous, n. sp. 



Dull ferruginous, with scattered white short hairs, prothorax one-half 

 longer than wide, sides slightly rounded, narrowed behind, coarsely and 



* O. elegantulus Summers, New Orleans, Our Home Journal, January 30th, 1S75, 

 and December 19th, 1875, does not belong to this genus, but to Cylan, a genus 

 thus far known only from India and Africa. It will be found under the family 

 Brenihidw. 



